Asymmetrically fed stability chamber for a gas burner

ABSTRACT

A gas burner assembly for an appliance has a gas stability chamber with a simmer flame port for providing a re-ignition source to primary burner ports positioned around the burner. The gas stability chamber has at least one primary stability chamber gas inlet and at least one secondary stability chamber gas inlet. The secondary stability chamber gas inlet is configured to provide a gas flow in the stability chamber with a velocity component that is offset from a radial direction of the gas burner assembly. This offset causes a flame at the simmer flame port to drift in the direction of an opposing side of the stability chamber from the secondary stability chamber gas inlet. As a result, the flamelet at the simmer flame port can more readily ignite the fuel exiting adjacent primary burner ports.

FIELD OF THE INVENTION

The subject matter of the present disclosure relates generally to a gas burner for the cooktop of an appliance.

BACKGROUND OF THE INVENTION

Gas burners are commonly used on the cooktops of household gas cooking appliances including e.g., range ovens and cooktops built into cabinetry. A significant factor in the performance of gas burners is their ability to withstand airflow disturbances in the surroundings, such as room drafts, rapid movement of cabinet doors, and most commonly rapid oven door manipulation. For appliances which comprise both an oven and cooktop, manipulation of the oven door can be particularly troublesome because rapid openings and closings of the oven door can produce respective under-pressure and over-pressure conditions within the oven cavity. These pressure changes may cause rapid expansion and/or contractions in the structures. As a result, a large amount of air passes through or around the gas burners with e.g., rapid opening or closing of the oven doors. Similarly for built in cooktops, pressure changes due to rapid manipulation of surrounding cabinets may result in large amounts of airflow through or around the gas burners.

Such surges of air around the gas burners, due to pressure disturbances in the surroundings, are detrimental to the flame stability of the burners and may cause extinction of the flames. This flame stability problem is particularly evident in sealed gas burner arrangements, which lack an opening in the cooktop surface around the base of the burner so as to prevent spills from entering the area beneath the cooktop.

The inherent cause of this flame instability is the low pressure drop of the fuel/air mixture passing through the burner ports of a typical burner used on the cooktop of an appliance. Although there is ample pressure available in the fuel, the pressure energy is used to accelerate the fuel to the high injection velocity required for primary air entrainment. Relatively little of this pressure is available at the burner ports. A low pressure drop across the ports allows pressure disturbances propagating through the ambient to easily pass through the ports, momentarily drawing the flame towards the burner head and leading to thermal quenching and extinction.

An additional problem is that rapid adjustments of the fuel supply to a gas burner from a high burner input rate to a low burner input rate often will cause flame extinction when the momentum of the entrained air flow continues into the burner even though fuel has been cut back, resulting in a momentary drop in the fuel/air ratio, and causing extinction.

A solution to the above-described problem is the use of a stability chamber as described e.g., in U.S. Pat. No. 5,800,159, commonly owned by the assignee of the present invention. In one embodiment, the stability chamber is formed from baffles extending radially outward from a burner throat and in a widening manner towards a simmer flame port. Primary burner ports are positioned proximate the simmer flame port. Fuel inlets to the stability chamber are positioned proximate the burner throat. The burner is able to maintain the simmer flame at both low and high settings so that the simmer flame can relight the flame at the primary burner ports when needed.

One challenge with stability chambers is the inherently slow velocity of the fuel mixture exiting the chamber. The slow velocity is necessary to make a stability chamber robust to disturbances but also reduces the flame's kinetic energy and associated ability to entrain secondary air. Drafts, whether induced by the local gas flow of the burner itself or by external influences, can push or pull the resulting lazy plume exiting the stability chamber into a flame from an adjacent burner port. When this occurs, the two flames tend to coalesce and become starved for air locally at the relatively higher flow rate of the coalesced plume. This in turn causes this plume of flame to further extend upwardly for more air and impinge on cool surrounding surfaces such as the cookware above the burner. The cool surfaces quench the flame, preventing complete combustion, and causing carbon or soot formation. Increasing the distance between the chamber and adjacent ports is often done to reduce this tendency to coalesce. Yet in doing so, the ability of the chamber to ignite the adjacent ports at low flow rates becomes increasingly unlikely.

Accordingly, an improved gas burner for an appliance would be useful. More particularly, a gas burner having an improved ability to relight while preventing or minimizing soot formation associated with a stability chamber would be beneficial.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides a gas burner assembly for an appliance that has a gas stability chamber with a simmer flame port for providing a reignition source to primary burner ports positioned around the burner. The gas stability chamber has at least one primary stability chamber gas inlet and at least one secondary stability chamber gas inlet. The secondary stability chamber gas inlet is configured to provide a gas flow in the stability chamber with a velocity component that is offset from a radial direction of the gas burner assembly. This offset causes, at lower firing rates, a flame at the simmer flame port to drift in the direction of an opposing side of the stability chamber from the secondary stability chamber gas inlet. As a result, the flamelet at the simmer flame port can more readily ignite the fuel exiting adjacent primary burner ports. This offset component becomes less and less influential at higher firing rates where coalescence and soot formation is more likely. Additional aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

In one exemplary embodiment, the present invention provides a gas burner assembly for a cooktop of an appliance that includes a burner body having an annular sidewall surrounding a main gas conduit having a gas inlet and a gas outlet. The burner body defines circumferential, axial, and radial directions; and the burner body has an upper surface. A plurality of primary burner ports are disposed within the annular sidewall of the burner body, surround the gas outlet, and are in fluid communication with the main gas conduit through the gas outlet. A cap is received onto the burner body. A simmer flame port is disposed within the annular sidewall, spaced along a circumferential direction from the primary burner ports, and is configured to provide a reignition source for the primary burner ports. A stability chamber is located adjacent to, and radially inward of, the simmer flame port. The stability chamber is defined at least in part by a pair of baffles extending along the radial direction, positioned in an opposing manner from each other along the circumferential direction, and projecting from the upper surface along the axial direction. The stability chamber is also defined by an end wall positioned radially inward of the pair of baffles, the upper surface of the burner body, and the cap. At least one primary stability chamber gas inlet is configured for providing gaseous fuel flow from the gas outlet into the stability chamber. A secondary stability chamber gas inlet is positioned along one of the baffles at a location that is radially outward of the at least one primary stability chamber gas inlet and is configured for providing gaseous fuel flow from the gas outlet into the stability chamber. The secondary gas inlet oriented to provide gas flow into the stability chamber with a velocity component that is offset from the radial direction so as to cause a flame at the simmer flame port to drift in a direction towards an opposing side of the stability chamber from the secondary stability chamber gas inlet.

In another exemplary embodiment, the present invention provides a gas burner assembly for a cooktop of an appliance. The gas burner assembly includes a burner body having an annular sidewall surrounding a main gas conduit. The burner body defines circumferential, axial, and radial directions. The burner body has an upper surface. A plurality of primary burner ports are disposed within the annular sidewall of the burner body, surround the gas outlet, and are in fluid communication with the main gas conduit. A cap is received onto the burner body. A simmer flame port is disposed within the annular sidewall, spaced along a circumferential direction from the primary burner ports, and is configured to provide a reignition source for the primary burner ports. A stability chamber is located adjacent to, and radially inward of, the simmer flame port. The stability chamber defined at least in part by i) a pair of baffles extending along the radial direction; ii) an end wall positioned radially inward of the pair of baffles; iii) the upper surface of the burner body; and iv) the cap. A pair of primary stability chamber gas inlets are configured for providing gaseous fuel flow from the gas outlet into the stability chamber. A secondary stability chamber gas inlet is positioned along one of the baffles at a location that is radially outward of the primary stability chamber gas inlets and is configured for providing gaseous fuel flow from the gas outlet into the stability chamber. The secondary gas inlet is oriented to provide gas flow into the stability chamber with a velocity component that is offset from the radial direction so as to cause a flame at the simmer flame port to drift towards one of the primary burner ports.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

FIG. 1 is a perspective view of an exemplary embodiment of a cooktop appliance of the present invention.

FIG. 2 is an exploded, perspective view of an exemplary embodiment of a burner assembly of the present invention.

FIG. 3 is a top view of the exemplary embodiment of FIG. 2.

FIG. 4 is a top view of a portion of the exemplary burner assembly of FIG. 2.

FIG. 5 is another top view of the exemplary embodiment of FIG. 2 with a schematic depiction of certain flames as more fully described below.

FIG. 6 is a top view of a burner assembly without a secondary stability chamber gas inlet.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

FIG. 1 illustrates an exemplary embodiment of a cooktop appliance 100 as may be employed with the present subject matter. Cooktop appliance 100 includes a top panel 104. By way of example, top panel 104 may be constructed of glass, ceramics, enameled steel, and combinations thereof. Top panel 104 may be part of a range or other appliance, or panel 104 may be a stand-alone appliance.

For cooktop appliance 100, a utensil holding food and/or cooking liquids (e.g., oil, water, etc.) may be placed onto grates 116 at a location of any of a plurality of burner assemblies 110. As shown in FIG. 1, burner assemblies 110 can be configured in various sizes so as to provide e.g., for the receipt of cooking utensils (i.e., pots, pans, etc.) of various sizes and configurations and to provide different heat inputs for such cooking utensils. Grates 116 are supported on a top surface 118 of top panel 104.

Burner assemblies 110 provide thermal energy to cooking utensils on grates 116. In particular, burner assemblies 110 extend through top panel 104 below grates 116. Burner assemblies 110 are also mounted to top panel 104. Burner assemblies 110 provide for combustion of a gaseous fuel to provide heat energy for cooking.

A user interface panel 112 is located within convenient reach of a user of the cooktop appliance 100. For this exemplary embodiment, panel 112 includes knobs 114 that are each associated with one of burner assemblies 110. Knobs 114 allow the user to activate each burner assembly 110 and determine the amount of heat input provided by each burner assembly 110 to a cooking utensil located thereon. Panel 112 may also be provided with one or more graphical display devices that deliver certain information to the user such as e.g., whether a particular burner assembly is activated and/or the level at which the burner assembly is set.

Although shown with knobs 114, it should be understood that knobs 114 and the configuration of cooktop appliance 100 shown in FIG. 1 are provided by way of example only. More specifically, user interface 112 may include various input components, such as one or more of a variety of touch-type controls, electrical, mechanical, or electro-mechanical input devices including rotary dials, push buttons, and touch pads. The user interface 112 may include other display components, such as a digital or analog display device designed to provide operational feedback to a user.

Cooktop appliance 100 shown in FIG. 1 illustrates an exemplary embodiment of the present subject matter. Thus, although described in the context of cooktop appliance 100, the present subject matter may be used in cooktop appliances having other configurations, e.g., a cooktop appliance with one, two, or more additional burner assemblies. Similarly, the present subject matter may be used in cooktop appliances that are part of an oven such as e.g., range appliances.

FIG. 2 illustrates an exploded view of an exemplary embodiment of a burner assembly 110 of the present invention while FIG. 3 provides a top view (with a cap 98 removed) of the same. Burner assembly 110 includes a burner body 120 that supports removable cap 98. Burner body 120 may be constructed as an integral piece that includes various features as described herein. For reference purposes, burner body 120 defines an axial direction A, radial direction R, and circumferential direction C.

A flow G of gaseous fuel enters burner body 120 through gas inlet 122 and travels along main gas conduit 96 to a gas outlet 124 where it will impinge upon cap 98. The gaseous fuel will then flow radially outward through a main fuel chamber 132 formed between cap 98 and upper surface 154 of burner body 120. The gaseous fuel will flow towards an annular sidewall 126 defined by burner body 120. In turn, annular sidewall 126 defines a plurality of primary burner ports 128, which are openings through which the gaseous fuel may travel to the exterior of burner assembly 110.

As shown, primary burner ports 128 are spaced apart from each other along circumferential direction C and surround gas outlet 124. Through gas outlet 124, each primary burner port 128 is in fluid communication with gaseous fuel flow G through main gas conduit 96. Primary burner ports 128 supply the main source of gaseous fuel that, after mixing with the surrounding air, is combusted to provide heat energy for cooking operations.

Gas burner assembly 110 also includes a simmer flame port 130 disposed within annular sidewall 126 and spaced along circumferential direction C from the primary burner ports 128. During cooking operations, particularly at low settings where the flow of gaseous fuel is low, simmer flame port 130 provides a reignition source for primary burner ports 128.

Gaseous fuel is fed to simmer flame port 130 from a stability chamber 134. As shown, stability chamber 134 is located adjacent to, and radially inward of, simmer flame port 130. Stability chamber 134 is defined in part by a pair of baffles 138, 140 that extend along radial direction R. Baffles 138 and 140 are spaced apart, positioned in an opposing manner along circumferential direction C, and project from upper surface 154 along axial direction A. For this exemplary embodiment, stability chamber 134 is also defined in part by upper surface 154, cap 98, and an end wall 136 positioned radially inward of baffles 138 and 140 on a toroidal projection 152.

Gaseous fuel from gas outlet 124 is fed to stability chamber 134 by a pair of primary stability chamber gas inlets 142 and 144, which are formed as gaps or openings between end wall 136 and radially inward ends 160 and 162 of baffles 138 and 140. For this exemplary embodiment, the two gas inlets 142 and 144 create an overall flow of gaseous fuel through stability chamber 134 that is primarily along radial direction R. In other embodiments of the invention, a different number of openings may be used for the primary stability chamber gas inlets and may be positioned at different locations relative to, or along, baffles 138 and 140.

Gaseous fuel is also fed to stability chamber 134 by a secondary stability chamber gas inlet 146 that is positioned along baffle 140. As shown, secondary stability chamber gas inlet 146 is located only along one side of stability chamber 134 and at a location that is radially outward of the primary stability chamber gas inlets 142 and 144. Gaseous fuel is fed to secondary stability chamber gas inlet 146 from gas outlet 124.

Secondary stability chamber gas inlet 146 is configured so as to provide gas flow in stability chamber 134 having a velocity component that is offset from radial direction R. Referring to FIG. 4, for this embodiment, gas inlet 146 is positioned on a top edge 164 of baffle 140 and is formed as a channel between surfaces 156 and 158 as provided by top portions 140 a and 140 b of baffle 140. Cap 98 and top edge 164 located between surfaces 156 and 158 also form channel 146.

Channel axis CA is parallel with surfaces 156 and 158 and is oriented so as to form an acute, non-zero angle α with the radial direction R or with the radially inward portion 140 a of baffle 140. In one exemplary embodiment, angle α is in the range of 0 degrees<α≦60 degrees. In another exemplary embodiment, angle α is in the range of 0 degrees<α≦45 degrees.

Additionally, baffle 140 has a length L along radial direction R. Secondary stability chamber gas inlet 146 is located a position P along baffle 140 as measured along the top edge 164 of baffle 140. For this exemplary embodiment, the ratio P/L is about ⅔ or more. However, other ratios for P/L may be used. Inlet 146 has a width W along radial direction R as shown.

The values for angle α, width W, and ratio P/L are all chosen so that secondary stability chamber gas inlet 146 imparts a velocity component to the gas flow through inlet 146 that is offset from the radial direction during low gas flow but has minimal effect when the burner is operating at high gas flow. FIG. 5 illustrates another top view of the exemplary burner assembly 110 with cap 98 removed from burner body 120 for purposes of explanation. As indicated by arrows F, gaseous fuel flows in stability chamber 134 through inlets 142 and 144. This results in an overall primary flow R₁ and R₂ along radial direction R.

As shown, a smaller amount of secondary gaseous fuel flow L enters stability chamber 134 through secondary stability chamber gas inlet 146. During periods of low gas flow from gas outlet 124, this secondary flow L causes a simmer flame S at simmer flame port 130 to drift in a direction that is towards an opposing side of the stability chamber 134 from the secondary stability chamber gas inlet 146—i.e. in a direction from baffle 140 towards baffle 138. As a result, simmer flame S at simmer flame port 130 is caused to drift towards a primary burner port 128 b that is adjacent to simmer flame port 130. If flames at ports 128 have otherwise been extinguished due to e.g., drafts as previously described, simmer flame S will ignite a flame P₁ at port 128 b that will spread to ignite flame P₂ at another port 128 and continue so along circumferential direction C until a flame is positioned at each primary burner port 128—including primary burner port 128 c.

In contrast, FIG. 6 illustrates a burner body 20 without secondary stability chamber gas inlet 146. As indicated by arrows F, gas flows into stability chamber 34 from gas outlet 22. A flow of gas B is created along radial direction R that creates a simmer flame S at simmer flame port 30. During periods of low flow when the flame at ports 28 may be extinguished, simmer flame S will eventually reignite flame P₁, P₃, or both. The flame will spread along circumferential direction C to reignite the burner at all ports 28 including e.g., P₂ and P₄. However, without the tangential velocity component provided by secondary stability chamber gas inlet 146, simmer flame S must be larger in size in order to quickly ignite adjacent ports 128. Consequently, at higher firing rates simmer flame S is larger and thus more likely to coalesce with flame P1 or P3 causing a non-uniform flame appearance and potentially soot formation. The present invention can advantageously avoid this problem while providing for reignition of the flame when drafts or other events cause burner 110 to be extinguished.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A gas burner assembly for a cooktop of an appliance, comprising: a burner body comprising an annular sidewall surrounding a main gas conduit having a gas inlet and a gas outlet, the burner body defining circumferential, axial, and radial directions, the burner body having an upper surface; a plurality of primary burner ports disposed within the annular sidewall of the burner body, surrounding the gas outlet, and in fluid communication with the main gas conduit through the gas outlet; a cap received onto the burner body; a simmer flame port disposed within the annular sidewall, spaced along a circumferential direction from the primary burner ports, and configured to provide a reignition source for the primary burner ports; a stability chamber located adjacent to, and radially inward of, the simmer flame port, the stability chamber defined at least in part by a pair of baffles extending along the radial direction, positioned in an opposing manner from each other along the circumferential direction, and projecting from the upper surface along the axial direction; an end wall positioned radially inward of the pair of baffles; the upper surface of the burner body; and the cap; at least one primary stability chamber gas inlet configured for providing gaseous fuel flow from the gas outlet into the stability chamber, and a secondary stability chamber gas inlet positioned along one of the baffles at a location that is radially outward of the at least one primary stability chamber gas inlet and configured for providing gaseous fuel flow from the gas outlet into the stability chamber, the secondary gas inlet oriented to provide gas flow into the stability chamber with a velocity component that is offset from the radial direction so as to cause a flame at the simmer flame port to drift in a direction towards an opposing side of the stability chamber from the secondary stability chamber gas inlet.
 2. The gas burner assembly of claim 1, wherein the secondary stability chamber gas inlet comprises a channel formed along one of the baffles.
 3. The gas burner assembly of claim 2, wherein the channel defines a channel axis that forms an acute, non-zero angle α to the radial direction.
 4. The gas burner assembly of claim 3, wherein angle α is in the range of 0 degrees<α≦60 degrees.
 5. The gas burner assembly of claim 3, wherein angle α is in the range of 0 degrees<α≦45 degrees.
 6. The gas burner assembly of claim 2, wherein the channel is located along a top edge of one of the baffles.
 7. The gas burner assembly of claim 2, wherein the channel is located away from the end wall along one of the baffles at a distance that is more than half the length of the baffle.
 8. The gas burner assembly of claim 1, wherein the burner body defines a toroidal projection around the gas outlet, and wherein the annular sidewall and the toroidal projection define a main fuel chamber for the receipt of gas from the gas outlet.
 9. The gas burner assembly of claim 1, wherein the at least one primary stability chamber gas inlet comprises a pair of primary stability chamber gas inlets positioned in an opposing manner about the stability chamber.
 10. A cooktop appliance comprising the gas burner assembly of claim
 1. 11. A gas burner assembly for a cooktop of an appliance, comprising: a burner body comprising an annular sidewall surrounding a main gas conduit, the burner body defining circumferential, axial, and radial directions, the burner body having an upper surface; a plurality of primary burner ports disposed within the annular sidewall of the burner body, surrounding the gas outlet, and in fluid communication with the main gas conduit; a cap received onto the burner body; a simmer flame port disposed within the annular sidewall, spaced along a circumferential direction from the primary burner ports, and configured to provide a reignition source for the primary burner ports; a stability chamber located adjacent to, and radially inward of, the simmer flame port, the stability chamber defined at least in part by a pair of baffles extending along the radial direction; an end wall positioned radially inward of the pair of baffles; the upper surface of the burner body; and the cap; a pair of primary stability chamber gas inlets configured for providing gaseous fuel flow from the gas outlet into the stability chamber, and a secondary stability chamber gas inlet positioned along one of the baffles at a location that is radially outward of the primary stability chamber gas inlets and configured for providing gaseous fuel flow from the gas outlet into the stability chamber, the secondary gas inlet oriented to provide gas flow into the stability chamber with a velocity component that is offset from the radial direction so as to cause a flame at the simmer flame port to drift towards one of the primary burner ports.
 12. The gas burner assembly of claim 11, wherein the secondary stability chamber gas inlet comprises a channel formed along one of the baffles.
 13. The gas burner assembly of claim 12, wherein the channel defines a channel axis that forms an acute, non-zero angle α to the radial direction.
 14. The gas burner assembly of claim 13, wherein angle α is in the range of 0 degrees<α≦60 degrees.
 15. The gas burner assembly of claim 14, wherein angle α is in the range of 0 degrees<α≦60 degrees.
 16. The gas burner assembly of claim 14, wherein angle α is in the range of 0 degrees<α≦45 degrees.
 17. The gas burner assembly of claim 12, wherein the channel is located along a top edge of one of the baffles.
 18. The gas burner assembly of claim 12, wherein the channel is located away from the end wall along one of the baffles at a distance that is more than half the length of the baffle.
 19. The gas burner assembly of claim 11, wherein the burner body defines a toroidal projection around the gas outlet, and wherein the annular sidewall and the toroidal projection define a main fuel chamber for the receipt of gas from the gas outlet. 